Bearing segment for typewriters



P J. KRUGER BEARING SEGMENT FQR TYPEWRITERS Filed Dec. 11, 1959 Patented Sept. 29, 1942 BEARING. SEGMENT FOR TYPEWRITERS' Johannes Kriiger, Erfurt, Germany vested in the Mien Property Custodian Application December 11, 1939, Serial No. 308,704 In Germany May 18, 1937 1 Claim.

The present invention relates to typewriting machines and particularly to an improved slotted bearing segment for supporting the pivoted type bars thereof.

In previous constructions, the bearing segments of typewriters have usually been made of cast iron which has been nickel plated to protect the same from'rusting. However, due to the porous nature of the material and the wearing of the nickel plating in use, rusting often occurs in such machines after standing idle for a time. This defect has been particularly troublesome in machines used in the tropics, resulting in sticking of the type bars and detracting in general from the ease of operation of the machine. The use of too much oil on the bearing parts to overcome the rusting is objectionable likewise as it results in adhesion of the type bars to the side walls of the slots in which they are pivoted due to drying and gumming of the oil. Furthermore, such cast segments must have the type bar guiding slotsformed by sawing after the segment is cast, thus preventing the positioning of the reinforcing rib connecting the webs of' the slotted portion of the segment in the most advantageous position since the rib must be placed so as not to be in the way of the saw blade or guides. Another disadvantage of sawed slots is that they cannot be made entirely uniform in width and although the variation may be slight, it has been necessary to provide different thicknesses of type bars to produce a proper fit in all slots. The sawing of the slots also produces minute ribs on the walls of the slots which wear quickly so that the permissible clearance between the type bar and. the walls of the slot is soon exceeded, thus producing faulty work by the machine.

In order to overcome the disadvantages of cast and sawed segments, it has been proposed to mount the type bars in separate elements in a row, screw fastened together, but such constructions have proven unsatisfactory due to the amount of hand work required for assembly, the accuracy with which the many parts must be made, and the fact that the parts become loosened in service.

It has also been proposed to form type bar segments of sprayed metal castings. However, due to the softness of the metal, they did not possess sufiicient wearing qualities. The use of hard metal wearing inserts and galvanically applied hard metal coatings on sprayed metal castings to improve the wearing qualities have also been proposed, but due to increased manufacturing costs and the fact that the bodies of such castings are not suificiently rigid for good service,. they have not proven to be a satisfactory substitute for the standard type of cast iron segment with sawed slots.

Due, therefore, to' the defectsof hitherto proposed substitutes, a return has been made to segments of cast iron with sawed slots, despite the disadvantages mentioned above.

It is a primary object of the present invention to provide a new form of type bar segment for typewriters and also a new method of manufacturing the same, which segment will overcomeall of the disadvantages of thevarious typesof'segments as heretofore proposed and. discussed above. 7

It is an object of the invention to provide a type bar segment consisting of an integral body of an artificial resin, preferably including inorganic admixtures and in which the webs defining the type bar slots and guiding the type bars'have a highly polished smooth surface impressed thereon in the forming operation due to the employment of polished mold parts.

Another object of the invention is to provide a segment of increased strength by forming the walls at the bases of the slots between the webs as curvilinear surfaces, made possible by the molded construction so as-to eliminate the sharp edges and shoulders which are necessarily present in sawed segments.

In order to provide ample guide means for the type bars and to insure good transation of material toall portions ofthe webportions of the segment, said web portions are extended Over the front face of the unslotted portion of the segment toward the center. Such an extension of the webs to provide extended guide surfaces for the type bars along the length thereof is not possible in sawed segments so that in such prior constructions, the type bars are unguided except immediately adjacent the pivotal area.

A further object is to provide a molded segment of a great strength formed of thermoplastic artificial resin, particularly for use in small typewriters with inclined segments, in which the slot defining webs are connected by an arcuate rib formed on a larger radius than the circumferential edge of the unslotted body portion of the segment and spaced therefrom, said rib extending across and joining the backs of the webs and having a flange portion extending forwardly between the webs to reinforce the same. Due to the molded construction, this reinforcing rib can extend forwardly toward the front edge of the webs to an extent appreciably greater than would be possible in sawed segments, thus greatly increasing the strength and rigidity of the webs.

Other objects and advantages of the invention will be apparent from the following detailed description of the invention with reference to the accompanying drawing.

In the drawing wherein a preferred constructional embodiment of the invention has been shown by way of example,

Fig. 1 is a central vertical section through a segment embodying the invention, being taken on the line 22 of Fig. 2, and

Fig. 2 is a front elevation thereof.

Referring more particularly to the drawing, l indicates the body portion of the segment which is molded by a pressing operation in one piece of a suitable artificial resin, preferably incorporating inorganic fillers. The radial type bar receiving slots 2 are completely formed in finished state in the molding operation by employing mold parts in which the slot forming webs of the mold are highly polished and are rounded at their edges so that in the molded segment the slot defining web portions join the body thereof on curved lines producing a curvilinear surface at the base of the slots 2 as indicated at 3 and the confronting walls of the segment webs have a smooth highly polished finished surface impressed thereon.

The webs 5 extend in a radial direction beyond the circumferential edge of the unslotted lower body portion 4 of the segment I, these webs being continued radially across and integrally joined with the lower part of the front face of the segment as indicated at 5:1 to form extended guides for the type bars which are to be pivoted between them.

As pointed out heretofore, the molding of the segment from a mass of thermoplastic artificial resin according to the invention permits the formation of the extended portions of the type bar guiding and supporting webs which could not be provided conveniently in sawed segments cut with rotary saws without weakening the body of the segment. Bore holes 6 are provided in the segment webs 5 for the reception of the usual fulcrum shaft used to mount the type bars, not shown, as will be readily understood by those skilled in the art.

An integral arcuate reinforcing rib I, extending concentrically and coextensive with the lower edge of the segment body extends across the back of the webs 5, being formed integral therewith and serving to connect them rigidly together for resisting bending strains. The rib 1, thicker at the back, extends forwardly between the webs 5 as at la, bridging across the space between the respective webs in the nature of struts. As will be apparent, the molded construction permits of forming the rib 1 so that the forward edge portion 1a thereof extends between the webs to a point much closer the front edge thereof than would be possible in sawed segments, thus increasing the strength and rigidity of the organization.

The use of artificial resin with suitable inorganic filler material for the segment has the added advantage that the same will not absorb or be affected by moisture and is not subject to change in shape in use.

An arcuate groove 8 is formed in the front face of the segment, above the webs 5, to receive'a hardened rebound ring. On its rear face, the segment is provided with small apertured lugs 9 for receiving the shifting bridges.

Various moldable artificial resin compositions may be employed in carrying out the invention, tropic-proof molded compositions, for example, those belonging to the group of phenolic resin compositions having wood flour as the chief filling material, being preferred.

While a preferred embodiment of the invention has been shown and described by way of illustration, it is understood that various modifications in the details thereof may be practiced without departing from the spirit of the invention within the scope of the appended claim.

I claim:

A bearing segment for typewriters comprising a segmental molded body portion of artificial resin, a plurality of molded tye bar supporting webs formed integrally with said segmental body and projecting radially from the circumferential edge thereof, each of said webs being formed with an aperture adjacent the extremity thereof for receiving the pivot rod of the type bars, and an arcuate reinforcing rib formed integrally with said webs and extending across the back thereof in radially spaced relation with respect to the circumferential edge of said segmental body portion, portions of said arcuate reinforcing rib being extended forwardly of said apertures between and integrally united with said webs to brace the same.

JOI-IANNES KRi'IGER. 

